Sure Bronze Bird.
Once I changed my rear ratio to 3.55 with the TH350, I was running about 3300 rpm on the highway at around 70 mph.
(these numbers might be out a little, but I think they're close)

I like taking my Bird on the highway as well as running around the streets. I'm not racing it, so I didn't have to take those factors into consideration.

The 200R4 offers the best of both worlds, in my opinion. Good (actually better) 1st gear ratio, yet an overdrive ratio for highway driving.
------TH350----200R4
1st---2.52-----2.74
2nd---1.52-----1.57
3rd---1.00-----1.00
OD--------------0.67

From what I understand, the 200R4 wasn't a real strong transmission back in the day, but there are a lot of updates they have developed over the years.
If you check out the websites of the guys selling them, they go into detail about the improvements.

Thers's a bunch of guys selling the 200R4 (TCI, Bowtie, Art Carr, etc) that all have the updates done to them.

I bought mine from Gear Star (http://www.gearstar.net/about/).
It came complete with trans, torque converter, TV cable, dipstick, synthetic oil).
Basically, everything you would need for the installation.

I also picked up a shifter conversion kit from Shift Works (http://www.shiftworks.com/firebird.htm#6869firebird). This kit includes the detent plate, linkage bracket and console selector plate.
When you're done, the console still looks original.

I'm now running about 2200 rpms at 65-70 mph. So it's really good on the highway.
With the low 1st gear ratio (and 450 ft lbs of torque ) it has lots of get up & go for me.

The TV cable was a little tricky to get set up correctly and I find it's easier to leave the transmission in 3rd around town, shifting it manually into OD when required.
Otherwise with the transmission in OD around town, it seems to "search" for the right gear shifting back and forth between 3rd and OD.

Overall, I'm really happy with the results of this installation.

If there's anything else you're wondering about, just let me know.
I'd be happy to post whatever I can.
Trevor